Flat flexible cable with pseudo-twisted conductors

Abstract

A flat flexible electrical cable includes a pair of pseudo-twisted conductors on a flexible dielectric substrate. Each conductor includes alternate straight and oblique sections. The straight sections of the conductors are generally parallel to each other and of uniform width. The oblique sections of the conductors cross each other at a crossover point. Each oblique section of each conductor is reduced in width uniformly in a direction from the straight-to-oblique transfer point of the respective conductor to the crossover point of the conductors.

We claim: 
     
       1. A flat flexible electrical cable, comprising: first and second pseudo-twisted flexible conductors on a flexible dielectric substrate having first and second opposite sides, said first conductor being on said first side of the substrate and said second conductor being on said second side of the substrate, each conductor including alternating straight and oblique sections with a straight-to-oblique intersection between said straight and oblique sections, the straight sections of the conductors being generally parallel to each other and of uniform width, the oblique sections of the conductors crossing each other at a crossover point, and each oblique section of each conductor decreasing in width uniformly in a direction from said straight-to-oblique intersection of the respective conductor to an adjacent crossover point of the conductors.   
     
     
       2. The flat flexible electrical cable of claim 1, including dielectric flexible films covering the outsides of the conductors. 
     
     
       3. The flat flexible electrical cable of claim 2, further including an adhesive between said flexible dielectric substrate and said flexible conductors and between said flexible conductors and said flexible films. 
     
     
       4. The flat flexible electrical cable of claim 1, wherein said crossover points define a centerline generally parallel to said straight sections of said conductors, and said straight sections of said first conductor being positioned in an alternating manner in two lines generally parallel to and on opposite sides of said centerline, said straight sections of said second conductor being positioned in an alternating manner in two lines generally parallel to and on opposite sides of said centerline, each of the straight sections of said first conductor being positioned on an opposite side of said centerline relative to said straight sections of said second conductor. 
     
     
       5. The flat flexible electrical cable of claim 1, wherein said cable includes a plurality of said first and second conductors. 
     
     
       6. The flat flexible electrical cable of claim 5, further including dielectric flexible films covering the outsides of said plurality of first and second conductors. 
     
     
       7. The flat flexible electrical cable of claim 6, wherein said crossover points of each of said first and second conductors define a centerline generally parallel to said straight sections of said conductors, and said straight sections of each of said first conductors being positioned in an alternating manner in two lines generally parallel to and on opposite sides of said centerline, said straight sections of each of said second conductors being positioned in an alternating manner in two lines generally parallel to and on opposite sides of said centerline, each of the straight sections of each of said first conductors being positioned on an opposite side of said centerline relative to said straight sections of each of said second conductors. 
     
     
       8. A generally planar flat flexible electrical cable, comprising: a plurality of pairs of first and second pseudo-twisted flexible conductors generally positioned within a plane, said first and second conductors being spaced apart in a direction generally perpendicular to said plane and having a flexible dielectric substrate between said conductors and within said plane, said conductors having a periodic shape with said first conductors being shifted longitudinally relative to said second conductors by one half of a period of said shape, said first and second conductors including a crossover point at which said first and second conductors of each pair cross over each other and are separated by said flexible dielectric substrate, said crossover points of each pair defining a centerline with said first and second conductors reversing locations on opposite sides of said centerline, each said conductor including a transition section extending from a peak location a maximum distance from its respective centerline to said crossover point, said transition section decreasing in width uniformly in a direction from said peak location to said crossover point whereby the width of each said conductor is at a maximum at said peak location and at a minimum at said crossover point; and a dielectric flexible film covering the outsides of the conductors.   
     
     
       9. The generally planar flat flexible electrical cable of claim 8, wherein each said conductor includes alternating straight and oblique sections, said oblique sections crossing the centerline of each pair of conductors and said straight sections of each conductor being alternatingly positioned on opposite sides of said centerline. 
     
     
       10. The flat flexible electrical cable of claim 9, further including an adhesive between said flexible dielectric substrate and said flexible conductors and between said flexible conductors and said flexible films. 
     
     
       11. The flat flexible electrical cable of claim 10, further including an adhesive between said flexible dielectric substrate and said flexible conductors and between said flexible conductors and said flexible films. 
     
     
       12. A flexible printed circuit member, comprising: an elongated flexible dielectric substrate having first and second opposite sides with at least one axis therealong;   a first flexible conductor disposed on said first side of said dielectric substrate, said first conductor comprising a plurality of first portions with at least one of said first portions of said first conductor having a pair of spatially offset first conductor sections disposed on opposite sides of said axis and having a pair of first crossover sections, one of said first crossover sections interconnecting one of said first conductor sections to the other of said first conductor sections and the other of said first crossover sections being connected to said other of said first conductor sections; and   a second flexible conductor disposed on said second side of said dielectric substrate, said second conductor comprising a plurality of second portions with at least one of said second portions of said second conductor having a pair of spatially offset second conductor sections disposed on opposite sides of said axis and having a pair of second crossover sections, one of said second crossover sections interconnecting one of said second conductor sections to the other of said second conductor sections and the other of said second crossover sections being connected to said other of said second conductor sections, each of said second crossover sections crossing one of said first crossover sections at a crossover point on opposite sides of said substrate, each of said first and second crossover sections decreasing in width uniformly as each of said crossover sections extends from one of said conductor sections toward one of said crossover points.   
     
     
       13. The flexible printed circuit member of claim 12 including flexible dielectric films covering said first and second flexible conductors. 
     
     
       14. The flexible printed circuit member of claim 12 wherein said first sections of said first conductor are substantially straight portions of said first conductor and are disposed generally parallel to said axis and said second sections of said second conductor are substantially straight portions of said second conductor and are disposed generally parallel to said axis. 
     
     
       15. The flexible printed circuit member of claim 12 including a plurality of sets of first and second flexible conductors. 
     
     
       16. The flexible printed circuit member of claim 12 wherein said first and second flexible conductors include electrical and mechanical interconnections through said dielectric substrate. 
     
     
       17. The flexible printed circuit member of claim 16 wherein said electrical and mechanical interconnection is achieved with vias extending through said dielectric substrate. 
     
     
       18. The flexible printed circuit member of claim 12 wherein said crossover points define a centerline along said axis. 
     
     
       19. A flexible circuit member comprising: a generally planar, flexible dielectric substrate;   a pair of first and second flexible conductors on opposite sides of said substrate and extending longitudinally along said substrate in a generally periodic pattern wherein said first conductor has first crossover sections that cross over second crossover sections of said second conductor at crossover points separated by the dielectric substrate, the crossover points of said first and second conductors defining a centerline with the first and second conductors reversing each other on opposite sides of the centerline, each of said first and second crossover sections decreasing in width uniformly as said crossover section extends toward one of said crossover points.   
     
     
       20. The flexible circuit member of claim 19 including dielectric flexible films covering the outsides of said first and second conductors. 
     
     
       21. A flexible printed circuit member, comprising: an elongated flexible dielectric substrate having first and second opposite sides;   a plurality of sets of first and second pseudo-twisted flexible conductors positioned on said dielectric substrate, each of said first pseudo-twisted conductors being on said first side of said substrate and each of said second pseudo-twisted conductors being on said second side of said substrate, each pseudo-twisted conductor having a generally periodic pattern with said first pseudo-twisted conductor being shifted longitudinally relative to its respective second pseudo-twisted conductor by one half of a period of said periodic pattern, each pair of said first and second pseudo-twisted conductors having crossover sections defining crossover points at which said first and second pseudo-twisted conductors cross over each other on opposite sides of said flexible dielectric substrate, each of said crossover sections decreasing in width uniformly as said crossover section extends toward said crossover point.   
     
     
       22. The flexible printed circuit member of claim 21 including flexible dielectric films covering said first and second pseudo-twisted conductors. 
     
     
       23. The flexible printed circuit member of claim 21 wherein said first conductor has substantially straight portions disposed generally parallel to said a centerline defined by said crossover points and said second conductor has substantially straight portions disposed generally parallel to said centerline. 
     
     
       24. The flexible printed circuit member of claim 23 wherein each set of said first and second pseudo-twisted conductors include electrical and mechanical interconnections through said dielectric substrate.